fix(kernel/expr): initialization problem
fix(kernel/expr): initialization problem

Signed-off-by: Leonardo de Moura <7610bae85f2b530654cc716772f1fe653373e892@microsoft.com>

johoelzl/lean,digama0/lean,leanprover-community/lean,leodemoura/lean,htzh/lean,fgdorais/lean,sp3ctum/lean,htzh/lean,htzh/lean,UlrikBuchholtz/lean,fpvandoorn/lean2,fgdorais/lean,avigad/lean,soonhokong/lean-windows,johoelzl/lean,leanprover/lean,dselsam/lean,soonhokong/lean-osx,eigengrau/lean,dselsam/lean,soonhokong/lean,fpvandoorn/lean,Kha/lean,Kha/lean,dselsam/lean,rlewis1988/lean,sp3ctum/lean,Kha/lean,leanprover/lean,javra/lean,c-cube/lean,soonhokong/lean-windows,digama0/lean,rlewis1988/lean,sp3ctum/lean,avigad/lean,johoelzl/lean,soonhokong/lean,levnach/lean,sp3ctum/lean,UlrikBuchholtz/lean,levnach/lean,Kha/lean,dselsam/lean,levnach/lean,levnach/lean,fgdorais/lean,javra/lean,javra/lean,fpvandoorn/lean,leodemoura/lean,c-cube/lean,avigad/lean,fpvandoorn/lean,leanprover-community/lean,c-cube/lean,fgdorais/lean,leanprover/lean,fpvandoorn/lean2,fpvandoorn/lean2,digama0/lean,leanprover-community/lean,soonhokong/lean-osx,soonhokong/lean,soonhokong/lean-windows,leodemoura/lean,fpvandoorn/lean2,leodemoura/lean,fpvandoorn/lean,levnach/lean,fpvandoorn/lean,johoelzl/lean,leanprover/lean,soonhokong/lean-windows,leodemoura/lean,soonhokong/lean-osx,eigengrau/lean,eigengrau/lean,avigad/lean,avigad/lean,htzh/lean,leanprover-community/lean,leanprover-community/lean,leanprover/lean,eigengrau/lean,soonhokong/lean,fpvandoorn/lean,Kha/lean,UlrikBuchholtz/lean,digama0/lean,UlrikBuchholtz/lean,digama0/lean,rlewis1988/lean,soonhokong/lean-osx,eigengrau/lean,leodemoura/lean,rlewis1988/lean,digama0/lean,leanprover-community/lean,fgdorais/lean,rlewis1988/lean,c-cube/lean,javra/lean,leanprover/lean,johoelzl/lean,javra/lean,UlrikBuchholtz/lean,htzh/lean,fpvandoorn/lean2,soonhokong/lean-windows,johoelzl/lean,soonhokong/lean,avigad/lean,c-cube/lean,fgdorais/lean,Kha/lean,soonhokong/lean-osx,dselsam/lean,sp3ctum/lean,rlewis1988/lean,dselsam/lean